The shaft of a conventional golf club having a heavy head invariably bends in a so-called primary frequency mode in mechanics when it is being swung. A typical bent shape is shown in FIG. 1 wherein 1 is the shaft, 51 the butt end, 51 to 5 is a rigid portion, 3 the head end, 4 the swing load at the head, 7 the rubber grip, and 8 is where the grip ends. Grip is a covering of the handle part of a golf club shaft which is about 25 cm in length, but only about the first 20 cm is being used to hold by a typical player. Grip is meant here as the handle part, about 20 cm of the shaft, where the hand actually holds. From end points 51 to 3, the shaft forms a downward bending curve. The time required for the bending shaft to finish a complete cycle of vibration is called frequency. Frequency depends on the mode which is the shape of the bending curve. The primary frequency mode is the slowest for the shaft to swing back from its maximum curved position to the straight, unstressed length again. When the shaft recovers to straight, the head should hit the stationary ball at the tee. A slow recovery, and for that matter a primary frequency mode, means a slow head speed.